looks like i'm gonna have to change out the pistons soon but still debating over what to get.......my gsr has s2 manifold, i/h/e, CTR cams, 64mm TB, hight flow cat.........i figure CTR pistons and mugen head gasket would give me the highest CR and ultimately, most power, but will i have problems running them on the street?....93 octane is all i use but is that sufficient enough for the high CR......else i'll get ITR pistons and the mugen HG.......also how dependable is it.......is it as reliable as stock........thanks for any info

 

i dont know too much about high compression and pistons and stuff,
but i have read that the CTR piston in a stock motor alone is not too streetable.

so with a mugen head gasket, i highly doubt your car will be streetable with the mods you have,

also, you would definately need to use higher octane fuel with ctr pistons and mugen head gasket.

but it would be darn sweeeeeeeet if you had all that together

 

I run CTR`s in an ls/vtec setup w/ no problems. Stuck w/ 91 octane lately too!

Ryan

 

dude, your CR will be over 12:1!!!
How about USDM ITR psitons and Mugen HG??? the CR should be about 10.9:1

 

omg man please do not do this... you would have to be insane. I wouldnt even run ctrs with a stock headgasket

 

Dude, I told you. BTW, an LSVTEC isn't the same as a B18C1 (to the person who posted that).

With the CTR's and a thinner headgasker, you'll be in the high 12's:1. You'd have to run a gallon of Race gas with every tank, and even then I'd bet money your motor would blow in a week (hot Texas weather). Unless you had a Knock sensing ECU, I wouldn't bother. With the USDM ITR's, you'll be at ~10.8:1. If you want more, the JDM ITR's will put you in the low 11's:1 which is plenty.

We don't want to be rebuilding this motor twice

 

and another thing, the piston-to-valve clearance would be reduced with the pistons and with the headgasket. If you want Compression, ITR or P3O pistons are good. -C

 

If you're gonna run it , I advise you get a rich ecu program like a skunk ecu and run beefier injectors. You may even still get some detonation.

Some people from this board run CTR's and claim no problem what soever. A cheap alternative to the mugen hg is a stock one with one layer removed.

I say go for it, we need more high compression na GSR's out there!

 

alright, so majority say it would be too high, so now the choice is:

CTR pistons alone vs USDM itr + mugen headgasket vs jdm itr pistons alone

anyone know the CR for each of these alternatives?

 

oh yeah, calvin, so is it safe to say that usdm itr's w/ mugen HG and jdm itr's yield about the same CR?

 

i have gsr pistons and a mugen head gasket...car runs fine...i use 93 octane gas always...no probs at all...also if anyone wants a mugen head gasket i have one for sale for 80.00...i has 1000 miles on it and is perfectly clean and in mint condition, removed it after i decided to rebuild my bottom end with 84.5mm pistons...so i can no longer use it


[Modified by sicilian2k1, 11:21 PM 9/17/2001]

 

Skip the headgasket. My vote is for Spoon balanced JDM ITRs (same price as JDM ITRs according to jdmhondaparts.com).

I'm not sure about the B18C, but the CR is 11.2-11.4:1 (people always argue) with the CTRs in B17a.

The CTRs with the Mugen HG shouldn't be high 12s. I'm thinking 12.0:1 or something. Still borders on streetable. I say no.

 

With a GSR head, the combustion chamber is smaller than a B16 or ITR head, so the sompression in a GSR motor with ITR pistons will be more than a stock ITR. Hope this helps

 

i have seen a few people run 11.5:1 CR with 92 octane, no problems. I think it would be brave to go much above that

 

Like I said, ls/vtec w/ stocker gasket and CTR`s..no problem on pump gas for 10k miles now.

Ryan

 

what head are you using vtecvooodooo?

 

b16..I`m cheap

 

yeah, skip the headgasket. just get pistons that will put you where you want to be

The USDM ITR pistons will put a GSR at around 10.8:1. Basically, the GSR head is worth ~.2:1 more compression than a b16a or ITR head on a b18C block. so if a JDM has, for example, 11.0:1 CR, then a GSR would have ~11.2:1 CR.

the headgasket is only going to give you 1-2hp at most and then your timing is going to be off which brings the cost of cam gears, and a timing light into the equation. HTH, -C

 

I don't know why everyone thinks that 12.x:1 compression is not streetable. I have Wiseco 12.5:1 compression pistons in my B18C5 that's been ported and polished, with some other goodies that Leitner and Bush have built into the motor, and my motor is streetable.

I'm limited in my choices of gasoline. Actually, I only have one choice, Sunoco Ultra 94. Other than that, I drive the car everyday to and from work even on the hottest days in summer with no problems.

If you're low on gas and have no Sunoco in site, you can fill up on 92 Octane and drive like grandma until you reach a Sunoco.

If you go high compression, just make sure your ECU and or VAFC is properly tuned to not only extract the most out of your mods, but also to protect your investment. May I suggest you take it to someone with access to a system like MOTEC. I did, and my engine's been healthy on and off the track for 2.5 - 3 yrs on high compression!


[Modified by 35mugen, 2:10 PM 9/18/2001]

 

it'll be fine i have many friend's that has done it with a milled head.....

 

thanks for all the help guys......leaning toward JDM itr pistons.......are the rings for the USDM and JDM itr pistons the same? just asking cuz i can get a good deal on USDM ITR ring set

 

same rings. B-series pistons are the same bore. -C

 

thought so.......looks like i'm gonna have to order new pistons sooner than i thought.......way too much smoke coming out of my exhaust

 

it is streetable but probably with octane boost
if you have overheating problems get the mugen thermostat
or cut your stock one after that no overheating problems
the temp drops low as hell when your on the highway
with the cut thermostat.i have no over heating problems
with my block guard. ive got 12:5:1 compression pistons
w/.25" overbore i just run octane boost
why dont you just get the je 12:5:1 compression pistons
might as well since your taking it apart anyway rods wouldnt hurt either

 

je pistons would be nice but i dont have 600.00 to spend on them........probably gonna go with some itr rods